We propose to continue our efforts in the resolution of the multiple forms of rabbit cytochrome P-450 and the development of specific antibodies. Reconstitution experiments are planned in which the inhibitory effect will be tested of the specific antibodies on the various drug and carcinogen-metabolizing activities of the monooxygenase system. In addition, we plan to pursue, by immunological techniques, the organ and tissue localization of components of the microsomal mixed function oxidase system. BIBLIOGRAPHIC REFERENCES: Porphyrin binding proteins in serum. U. Muller-Eberhard and W.T. Morgan, Ann. N.Y. Acad. Sci. 244: 624-650, 1975. Bilirubin production from erythroid sources. U. Muller-Eberhard and E.F. Johnson, JAUNDICE (Plenum Press, New York) pp. 69-83, 1975.